Fossil Record
The fossils have similar structures and functions that present day organisms in this taxonomic group have. The spiders in the amber look much like the spider species now alive. The jumping spiders in the amber are ancestors of jumping spiders today and share the same behavior of catching prey. The other imprint fossils show evolution because they resemble organisms in this taxonomic group but are slightly different. This shows that they have evolved and changed. The horseshoe crab ancestor fossils are the most different from modern horseshoe crabs. They have similar habits of catching food and moving but look different externally. The spider fossils all look like present day spiders of different species. They have the same number of legs, appendages, and all have segmented bodies. The fossils also show signs of exoskeletons like every organisms in Chelicerata has.